Nothing wrong with more Dusk Leather, and Iron Giant Cores are supposed to be rare procs - it's just that the Iron Giant Scraps are much more rare. Now, about those Toybox Schemata though.

I wouldn't be surprised if the airship materials become mats for other housing items or future airship parts though, and since I don't visit the <S17 areas that much I'd just throw those mats on a FC alt and stow them away just in case.